Crystal Structure of Triphenyl-7-cyclohepta-1, 3, 5-trienyltin, a Fluxional Organometallic Molecule

The crystal structure of triphenyl-7-cyclohepta-1, 3, 5-trienyltin has been determined from single-crystal X-ray diffraction data. The atoms were located by the use of a three-dimensional Patterson map followed by successive Fourier syntheses of the electron density. Refinement of the structure by the least-squares method resulted in an R = 0.061. The compound crystallizes in space group P2 with a = 10.928 á, b = 12.081 á, c = 11.733 å, a = 120.96°, β = 119.35°, and y = 94.83°. The molecule consists of an approximately tetrahedral triphenyltin ligand (T-bonded to a monocyclic seven-membered ring with alternating C-C distances indicative of considerable double bond character and with a nonplanar boat conformation. This structure is unlike that previously assigned to other fluxional cycloheptatrienes. © 1972, American Chemical Society. All rights reserved.